Applying the Seamoth Solar Charger to a Seamoth gives it almost unlimited Energy during the day in low depth.
Although these modules have a cumulative effect, they are so effective in their operating range that one module is more than enough.
The Seamoth Solar Charger recharges the Seamoth's Power Cell when exposed to sunlight. At the surface, during the day, one Seamoth Solar Charger gives 1% of energy every second. This value is lower during sunrise and sunset, which are the first and last five minutes of the 20 minute in-game day.
Seamoth Solar Charger have cumulative effects. Four of them recharge the Seamoth at a rate of 4% per second at the surface.
The power generated by a Seamoth Solar Charger decreases with depth. One module is powerful enough to charge a moving Seamoth up to 150m depth. Two are enough up to 175-200m.
Below 200m, Seamoth Solar Charger modules have a very weak charge rate, not even enough to sustain the Seamoth idle energy consumption (1% every 16s).